<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>03-回调ref中回调执行次数的问题</title>
</head>

<body>
    <!-- 准备好一个容器 -->
    <div id="test"></div>
    <!-- 引入react核心库 -->
    <script type="text/javascript" src="../js/react.development.js"></script>
    <!-- 引入react-dom，用于支持react操作DOM -->
    <script type="text/javascript" src="../js/react-dom.development.js"></script>
    <!-- 引入babel，用于将jsx转换为js -->
    <script type="text/javascript" src="../js/babel.min.js"></script>

    <script type="text/babel">  //此处一定要写babel
        //创建组件
        class Demo extends React.Component {

            state = { isHot: true }

            showInfo = () => {
                const { input1 } = this;
                alert(input1.value);
            }

            changeWeather = () => {
                //获取原来的状态
                const { isHot } = this.state;
                //更新状态
                this.setState({ isHot: !isHot });
            }

            saveInput = (c) => {
                this.input1 = c;
                console.log('@', c);
            }

            render() {
                const { isHot } = this.state;
                return (
                    <div>
                        <h2>今天天气很{isHot ? '炎热' : '凉爽'}</h2>
                        {/*<input ref={(c) => { this.input1 = c; console.log('@', c) }} type="text" />&nbsp;<br /><br />*/}
                        <input ref={this.saveInput} type="text" />&nbsp;<br /><br />
                        <button onClick={this.showInfo}>点我提示输入的数据</button>&nbsp;

                        <button onClick={this.changeWeather}>点我切换天气</button>&nbsp;

                    </div>
                )
            }

        }

        //渲染组件到页面
        ReactDOM.render(<Demo />, document.querySelector('#test'));
    </script>
</body>

</html>